...I strongly feel that the best approach is to write the XS code to be *very* C-centric...

This sounds like a tool that would take an API description of an external library and generates the perl modules source for the thin layer from that. Does such a beast exist already (not thinking about h2xs, as that is only fetching constants, right?)

Update:So you mean you should use SWIG to get the thin Perl layer and work from there?